The proposed invention relates to a circuit of a fault detection device for light emitting diodes (LEDs) in the outside lights of motor vehicles, which contains at least one string made up of LED diodes.
At present, when not only classical incandescent bulb lamps or halogen lamps but also in ever increasing extent lamps based on light emitting diodes are being used in motor vehicles as an outside light source, there are a number of circuits for fault indication in the strings of connected LED diodes. These circuits, which are designed as electronic circuits based on semiconductor components, are all protected by patent documents.
The circuit according to DE10131824A1 for detection of faults of the individual diodes in a LED array in a vehicle is based on comparing the potentials with reference potentials of data pertaining to the main driving potential by means of comparators.
The circuit according to U.S. 2006170287A1 also uses comparators for the detection, picking off the voltage on the string of LED diodes divided into two parts, where one section of the string contains a single LED diode.
The circuit according to EP2487998A1 is a solution for identification of at least one defective LED diode in the string, where an inspecting unit is connected to the midpoints of parallel strings of LED diodes and a resistance divider.
The circuit according to WO2008141384A1 is a device for determining the fraction of defective light emitting diodes by using a differential amplifier, where the strings of diodes are connected across a resistance divider to this amplifier.
In these solutions, their properties and thus their uses and advantages or disadvantages and limitations are essentially determined by the electronic elements used and their mutual connection for a given specific application, the number of LED diodes, and so on.